Automatic brake-adjusting mechanism



Nov., 173', 1928.

C. O. ANDERSON AUTOMATIC BRAKE ADJUSTING MECHANISM Filed March 26, 19272 Sheets-Sheet. l

o o. ANDLRSQN.

@Hornung 1,691,325 f "`C.`O ANDERSON Nov. 13, 1928.`

AUTOMATIC BRAKE ADJUSTING MEGHANISM Filed March 26, 1927 2 sheets-sheet2 1.4 l f5 1H 7 44 lll G. O. ANDERSON. l-www0@ anotan,

Patented Nov. 13, 1928.

UNITED `sra'rss CHARLES o. ANnnnsoN, or OMAHA, NEBRASKA.

AUTOMATIC BRAKE-ADJ'TIS'IIIIll'G` MECHANISM.

Application filed March ze, 1927. serial/No atasco.

My invention relates to railway brake mechanism, and especially toautomatically operating` means for adjusting the brake mechanism tocompensate for wear of the brake-shoes and maintain a substantially confstant slack or clearance between the brakeshoes v.and wheels when thebrakes are in release position, It is theobject of my present inventionto provide, in brake-adjusting lo mechanism ot the above character,certain f relinements ot' structure whereby to reduce to a minimum thewear of the mechanism dueto vibration, lack of lubrication, and theintro..-

duction ot abrasive `materials into the work- 5 ing parts. A furtherobject of my invention is to provide means vfor preventing excessiveaction of the adjusting` means, suoli as to'cause separation of theadjusting-screw and the head in which said screwV works. A furtherobjectis to .provide `means for preventing` looseness between theworking parts `ot `the adjuster, whereby to enable operation thereot bythe relativelv small resistedl movement ofthe brake-levers so-called*'beamless brake-riggine, wherein the brake-shoes are closely associatedwith the truck-levers instead oi. beine` carried at the ends of brakebeams to which thcftruck-levers are connected Aat the center'. Y

In the accon'ipanying drawings Fig. 1 is a loneitu din al section of atruck h avingjY applied to the brakedevers at one side thereof an adjListing; mechanism embodying` my invention,

Fig; 2 a plan view of the same, Fig; 3 is adetail end View olftheadjusting"mechanism and a portion of the live truck-lever, Fi 4 is adetail. transverse section on ftlieline--LlA ot Figs. 5 and. 6, F .is aside'view noi the adjusting mechanism, Fig. G is avloncjitudinal sectionot thesame, Fig. `6 is a side 'View` partially in longitudinal section,yshowin I a modified structure.A Fi i? is a plan view of the same..FigiK 8 is a detail longitudinal sect-ion showing); a specialdevice forpreventing' looseness between :the adjusting-screw n nl) el [i and head,and Fia. 9 a detail transversel section on the line 9;'9` of Fig. 8.

Reterrius,r to Figs.` 1 and?, there are shown portions ojt a truck of atype which ,has recently come into use for electric railways, an dwherein the `brakcfriajgring is commonly designa tedas beamlcss althoughin tact the luake-shoes arc carried on .brake-beams. In

y truclfzs of this type. in order to provide space lor elect-r i motorsliunghetween the axles 1G .and the sheams ofthe truclotrame, the

live and ydead trucklevers otfthe brakerigging are not connectedwitlrthe `central parts `oit/the bral-e-beams 12, and the main`transverse portions of said beams are arranged silbstantially beneaththe bolster 13. In `this class of'brake-rigging, in order to attainproper equalization ot' the brakingpressure at the brakefslioes 141-,.there are employed on leach truck two live-levers and two dead-levers1b, one pairthereof ,being arranged at each side .of the truck adjacentto the inner sides o'l' the wheels 17, and the uoperends of thelive-levers beingr connected with each other byv transversely extendingrequalizingig-leverr 18 to which .the braking power is applied. Therelease-springs 19 are also connected with said eqiializing-lever 18.The upper end of each .dead-lever is fulcrumedon a link 20 connectedwith kthe cross beam 11. The `intermediate portions of the levers land16 areconnected with the brakebeams 12 by brackets 21 which `aresecuredito n said beams close to the 'ends thereof on which the shoes16E are attached, 4and the brake-shoes and beams are supported byhanger-links 22 pivotally connected with the sideirames `23 'of thetruck. In .the illustrated structurethe lower ends of the levers 15 and16 areopera tively connected with eachother by my iniprovedbrake-adjuster, which is KLautomati- `cally extensible longitudinally tocompensate for wear of the brake-shoes.

ln brake-rigging of the class above mentioned, and in other cases, suchas in 'locomotive truckand driver brakes, where the brakelevers areclosely associated with the brake shoes,.without the interposition ot aconsiderable length `of brakebeam, `the movement of the leversk inapplyingv and releasing the brakes is relatively small, becausesubstantial.

l-y all movement. ot `the levers is ,immediately i effective upon thebrake-shoes, and after the brake-shoes are in Contact with the wheelsvery littleexcess movement of the ,levers is required to compensate forspringing ot the brakefbeams as the braking pressure is in creased. Inapplying, to such brake-rigging,

automatic slack adjusting means which de pends `for its operationquponvariations Lin the `angular relation ot thelive-lever vand the connecting member ibetween jsaid lever and the dead-lever, theadjustingmeans must be of such construction .that it willoperate.etticiently, and continue to so operate, without the excess travel ofthe truck-levers usually caused by springing of the brake-beams; and

rigging ot' the special types above noted.

The adjuster mechanism is 'best shown in Figs. 3, 4, ,5, 6 and?, and,referring to'said gures willbe seen thatat the end adjoining thelive-lever l5 there is a iorkedhead 24 whiclrstraddles the `end of theliveflever and "is pivotally connected therewith by the pin 25. The jawsof said forked head have upwardly extended cheek-plates 26formedintegrally therewith and adapted to closely embrace the sides ot thelever, as best shown in Fig. 3, for a purpose which will presentlyappear.k A portion of the pin 25 is extended. laterally Aof the head to`form a ulcrum for the bell-crank or rocker 27, which is retainedthereon a nut 28 screwed upon the thread-edend of the pin, a coil spring29 beingdisposed between said nut and the hub ot the rocker tofrictionally restrain .movements oliy the rocker about .the pin, and tothus reduce wear and rattling of these parts. One arm of the rockerextends approximately horizontally and terminates in a ball 30 whichlits within a socket formed by a U-shaped flange 3l on the side of theclutch-sleeve 32. The

rother arm of the rocker extends up approximately parallel with theleverl, and has a forked upper-end portion which straddles the laterallyprojecting end of the ralorum-,pin 33 which connects the lever with thebracket 21 ot the brake-beam. One side of t-he forked end of the arm isformed by a finger 34 which has a threaded shank screwed through themain part of the arm, whereby the space bc'- tween the jaws ot the forkmay be adjusted., a lock-nut bein provided on the threaded shank torholding the saine in adjusted position. L A j *n The head 24 has`atubular body-portion 36 over which the clutch-sleeve SQI'it-srotatably, and through wiich isextended the rotatable adjusting-rod 87,i VVithin'said tubular portion 36 said rod has a conical shoulder oroiifset 38 which tits within a conical seat provided within the borcofthe rhead, said shoulder being' held against said seat bythe pressureof a spring 39k disposed around the reduced end-portion ot the rod andretained thereon by a nut 40 screwed yupon the threaded end of saidreduced portion. f Upon the` rod 37 adjacent to the end ci. the tubularrbody 36 isV disposed a conical clutch-collar4l which is secured to vtherod by a transverse pin 42.` Said collar 4l is tudinally of therod totrictionally engage said seat with the clutch-collar, by means of aspring' 43 disposed around the rod at the end of the sleeve and heldagainst the samel by a collar 44 secured to the rod by a transverse npin 45, as shown in Fig. 6. The main portion oit the rod 37, at'th-e endopposite the clutch mechanism, is threaded and screwed into the"threaded intermediate portion oit a tubular chambered'end-portionsofthe head 46, ther open end osaid head being extended to nor mallyengagethe smooth or Unthreaded portion ofthe rod, and thus forming the guide5() for holding the head and rod in alinement additionally to thescrew-threaded engaging portions of said members. In the side oitv the:d 46 adjacent to the closed end thereof an opening is formed, which isnormally closed by a screw-plug '51. By connecting a greasegun with saidopening a 'suitable lubricant may be forced into and through the head,so as toliow toward the open end thereof, past the adjusting-screw, andthus tend to eject from the bore of the head dirt, grit or abrasivematerial which may have entered the same. The chambered end-portions ofthe head forni reservoirs for retaining a quantity of grease sufficientto lubricate the screw during an extended period o't'use. At the upperside o' the threaded intermediate portion of the head 46 a tubularbossris Formed thereon, the outer end ot' the openingthereot being`normally closed by a screw-plug 52. At the inner end of said opening,adjoining the screw` is disposed a ballfwhich is pressed yieldinglyagainst the Vscrew by a coil spring- 54 disposed between the ball andthe plug 52, as shown in Figs. 4 and 6. Near the end of theadjusting-screw a notch or recess 55 is formed in the side thereof. oneside otsaid notch being radially undercut so that when the ball dropsinto the notch, as shown in Fig. 4, it will Vpievent further rotation ofthe screw in the direction tending to withdraw the screw 'from the head.The rother side of the notch is so inclined that when the screw isturned so as to `enter the head the ball will be liited out of the notchand the turning move` ment not interrupted.

For Ausc where the adjuster is subjected not n only to lateral rorwhipping stresses but also to longitudinal shakingand vibration, it isdesirable to prevent wearwol the adj Listing-screw and the threaded partof the head, by main-V taining between the head and screw a longitudinalpressure whichA is constant in direction. This result is attained by thespecial Cil means illustrated in Figs. 6 8and9 wherein the guide-member50.` `at the open end of the4 hea-e146" is formedasapaclring-glandscrewed into `the-head, the glandfbeing recessed at itsinner end to receive a packing 56 which is`engaged by the end of asleeve57 fitting slid ably over Athe rod 37. At its inner end the sleeve 57engages a spring 58 disposed about o1 the head, whereby rotation otthejn'ut within the head is prevented, `while longitudinal movement' 1spermitted. In asse1nbling the parts the nut 59 is inserted edgew-isethrough the open end of the hea-d, and Vturned to a transverse positionafter the projection 59 isinposition to enter the pocket 60. The

rod is then screwed `through the nut, so as to project slightly past theinner face thereof, before starting to enter the adjacent threadedportion of ,thehead When the screw is started in said threaded portion,the nut wi-llmaintain its longitudinal position relative thereto, as thcrotation of the screw will cause it to advance equally through both thenut and theA head. rllhe assembly is con'ipleted lby inserting thespring `58 and sleeve 57,'then screwing the gland `into the head,whereby the spring 58 is compressed against `the vside of the nut, whichis thus caused'to exert a rthrust uponthe adjusting-screw. The strengthof the spring 58 is such that the longitudinal pressure be# `tween the`parts remains constantin direction, regardless o'l any 4shaking orvibration rto which the saine are subjected, and wear of the threads byrattling or hammerig from such vibration is thereby reduced to aminimum.

'ln' considering the operationoff the adjustr as a whole, it will beiirst noted that the clutch-sleeve is pressed against the clutchcono #ilwith a constant and uniform pressure, proportional to the strength ofthe spring a3, and any rotational movements of the sleeve thus tenduniformly to `be imparted to the adj usting-screw or rod'37 by the.frictional clutch connection.` The conical shoulder 38 of the adj1usting-rod, by being pressed into the seat therefor in the head 24,`terms a clutch-like irictionallconnection between said'4 head and theadjusting-rod. The spring 39' keeps thelongi'tudinal pressure at .theconical j shoulder constant in directionas the pressure or said springis greater than any tensile stresses to which the adjuster is normallysnbg vjected, but the `total pressure and the result.- ing riction atthe shoulder is variable, being increased by the longitudinalcompression .ot the adjuster when the brakes'rare applied, andbeingdecreased as the brakes are released, `'lllhere is a similar variationin the rictional resistance to rotation oi lthe adjustingscrew cationsoi the brakes will within the engaged portionoot the head it. Thevariationso'f friction, both at thehead 4.6 and atthe shoulder 88, areinconsequential during `the tree yor unresisted portion of thebrake-applying movements, before the brakeshoes are actually engagedwith `the wheels, but aiter suchengagement occurs the friction increasessubstantially in proportion to the `brakiiig-pressure exerted upon theslices.

` During' a normal brake-applying ,move ment` of the `livedever,such asoccurs when thefslaclr or clearance betweenthe brake-shoes andw'heels4is not excessive, the change in the angular relation ot the live-leverto the ad-y juster mechanism merely causes `the ulcrurnpin to movebetween the aws o'l' the rocker 27, andv vcauses no` movement of therocker `relative tothe head 2l. Then Vthe slack is excessive, however,the increased movement of the `live-jlever in applying the'braikescauses the pin 33 to engagethe linger or j aw 34 ofthe rocher vand tomove the latter slightly about its iulcrum on the pin'25. Such movementof the rocker is communicated to the clutchsl eve by the ball-head 30oi" the'lower rocke farm7 causing the clutch-sleeve to be rotated Lglitly relatively fto the headt, and `when the brakes are thenreleasedthe movement is reversed and `the clutch-sleeve is rotated slightlyinthe opposite direction7 Theseosf cillating, oralter'nating rotative,movements ofthe clutch-sleeve tend to be imparted by said'sl'eeve totheadjusting-rod 37, by reason of the constant frictional connectionbetween the clutch-sleeve and the collar lll' onsaid rod. i, e

It will be obvious that ift the movementsin both directions be impartedequally tojthe adjusting-rod no effectiveadjustmentoi the rod will becaused, and the length ot the brake lever-connection, formed byk theheads 24e and a andthe rod 37, will be unchanged. Actuation oft the rod37 occurs, however, when the clutch connection between the sleeve ?2 andcollar 'il is caused to slip during the movement in onedirection. j Theclutch-friction is sonproportioned that such slipping of the clutch`connection will occur during the resisted portieri of the brakeapplyingmovement, or after `the brake-shoes have engaged the wheels and 'begunto exert some pressure.

thereon, whereby thelongitudinal compression of the`brakelever-connection causes an increase oit the irictional resistanceto rota tion olf the screw f'within the head 46 and oi the,conicalshoulder 38 within the seat therelfor in the head After suchslippage off theclutchhas occurred during a brake-applying movement,then at the end of the succeed# ing brake-releasing movementtheadjustingscrew is turned slightly in the direction requ'ired'itoelongate the truck-lever-connection and reduce the slack.

lit a suflicient reduc-` tion ofthe slack is effected, subsequentapplicause i no movement ofthe rocker and clutch-sleeve,'buttheadjustbralre-slioes, and t ing action will be continued at eachapplication and release oit the brakes Liintil the eXcesf ing means, isthe resisted motion which occurs atterthe brake-shoes have engaged the'wheels, and subsequent to the tree motion during which the brake-shoesare merely being moved toward the wheels. Gbviously, inr brake-rigL ne;et the types first herein mentioned, or in vwhich the brake-lever areclosely associated with brake-shoes, the resisted portion oi" thebrake-applying motion oit the levers is ot small eitent andis merelythat which results from the sli l' t tie resilience o'tthe truck-leversie slight displacement 'ot the wheels ot' lthe truck, allowed bylooseness ot the journal-boxes and resulting trom lthe brake-pressureagainst thewheels, In order that the limited amount yoit resisted motionot the levers may be tully etfective in actuating the adjuster',substantially all looseness and lost motion between the parts ot theadjusting mechanism must be eliminated, and wear thereof compensated sotliatlc-oseness will not occur after a period ot use. ln my improvedadjuster the tirst oit tl e several means, employed tor theftoregoingpurpose, consists in the'provision et the cheek-plates 26 on the head24. ASaid vcheelcplates limit to a mini mum any rotational movement ofthe head 2a'- about the aXis oit the adjusting-rod 3'?, which mightotherwise result :trom looseness ot' the pin 25 which connects said head24C with the live-lever l5. The second means iter. limiting or reduciiiglost mot-ion in the adjusting device consists in the extension or' thered 3i' entirelyY through the' head 24, and the provision ot the spring39 upon the extended portion ot the rod, whereby the shoulder 38 is heldiirmly seated in thchead, rattling and wear between 'the head and rod isminimized, and a deiinite normal or average friction is assured betweenthe head and rod. The next ta ctor in the elimination of lost motioninthe adjuster mechanism is the mounting oit the utehsleeve upon theadjusting-rod beweengthv chitclrcone or collar land the prinet lf3,leaving the clutch-sleeve tree, for

ndi-nal n'ioveinent relative to the head I parts' intermediate the 2&1-,and thereby assuring a 4constant 'li'iction' dless or the' amount rordirection et longitodinal,stressesk the clutch connection, re.

inthe brairedenier-connection. The extension et the head i6longitudinali to cover the threaded,portion ofthe'ad Listing-rod at alll l b positions or adjustment thereof, assures etlicient lubrication otthe adjusting-screw, protects the screw-tl'ireads tromy corrosion,exchicles dust and abrasive material trom the screw', and provides thesupplemental guide to` assist in maintaining' the aliiieinent et randthe head and screw. The lock yor latch device, formed by the ball 53 andthe notch 55 in the adjusting-screw, prevents the accidental withdrawalof the screw from the head i6 by the continued operation of ytheadjusting means, should the renewal ot worn brakeshoes be neglected, orloss or breakage or parts occur, tending to cause the extension ot theadjuster bey-ond a proper rangeot adjustment th reot- Finally, the.provision of thenut 59 and the spring 58, in the special constructionshown in 8, causes a longitudinal c pressure, constant in direction,between ther i.istiiig-screw and the'threaded part ot' the read +16, andthus prevents longitudinal play,

rattling and wear between said screw; y f

New, having described my invention, what l claim and desire kte secureby Letters Patent is: l f

l. ln an automatic slaclrnadjuster Jfor brakes, a brake-levenconnectioncomprising terminal heads connected with the brake-lehead and the vers,and an intermediate rod connecting said heads androtatable relativelythereto, a portion ot sai(L rod being threaded and engaging athrewledportion oit one head, means for maintai ing between the rod and theother head a longitudinal pressure Constantin direction, aclutcl'i-sleeve.mounted rotatively iiion said rod having a constantvfrictional engagement therewith, and means for actuating saidclutch-sleeve in directions alter-y nating the brakes are applied andreleased.

2. In aslaclr-.ac-jiister for brakes, abralrelever-connection comprisingterminal heads pivotally connected rwith the brake-levers, an

intermediate rodconnectine said heads and 'rotatable relatively thereto,a portion of said rod'being threaded and engaging a threaded portion otthe adjacent head, and means for maintaining between said rod and eachof the heads a longitudinal pressurevvhieh is con stant in direction. ni

8. In a slack-adjuster for brakes, a braken lever-connection comprisingterminal heads and an intermediate,threaded rod connecting kico saidheads and rotatable,relatively thereto to vary thelength oit theconnection, means for yrotamting said rod, means pivotally connectingsaid headsfn'ith the brake-levers, and means termed integrally withonefof the heads and closely embracing the sideso't the respectivebrake-lever ata substantial distance from the pivotal axis, whereby topre- ,vent rotative movement otsaid head relative to said lever aboutthe"rod-anisvrhen the pivotal connection of ythe head and lever becomesworn and loose.4 c i i 1l. ln aslaclr-a'djuster for brakes, aybrakelevenconnection comprising terminal heads n pivotally connectedwith the brake-levers, and an .interinediat rod connecting said heads,said rod having at one rend a screw- VAthreaded connection with oftheheads isc part engaged by the threaded portion of trie and havingat theother end a shouldered reduced portion extending through the 'other headand rotatable therein, the shouldered portion engaging a seat thereforin said head,

disposed upon the threaded portion of the i adjusting-rod within thetubular body Vbetween said guide and the threaded part of the body, saidnut and the tubular body inter'- engaging to prevent relative rotationthereof, and a springl disposed about the rod between the guide and saidnut for pressing the latter longitudinally toward the threaded part ofthe body.

6. In an adjustable brake-lever-connection,

an adj usting-screw, a head having a threaded portion engaged by saidscrew, a nut disposed upon said screw, means for preventing relativerotation of said nut and the head, a spring engaging said nut andpressing the same longitudinally of the screw, and an abutment held infixed longitudinal relation to the head and engaging said spring to holdthe `saine against the nut.

7. In a. slack-adjuster for brakes, a brakelever-connection comprisingterminal heads connected with the brake-levers, and an ad justing rodconnecting said heads and rotatable relatively thereto, a portion ofsaid rod being threaded and engaging a threaded portion of one head, aclutch-sleeve mounted rotatively upon said rod, means for maintaining auniform frictional engagement between said sleeve and the rod, means foractuating the clutch-sleeve in directions alternating as the brakes areapplied and released, and means formaintaining between saidadjusting-rod and each of the heads a klongitudinal pressure which isconstant in direction.

8. In a slackeadjuster for brakesga brakelever-connection comprisingterminal heads pivotally connected with the brake-levers, and anadjusting-rod connecting said headsA and rotatable relatively thereto,"aportionV of said rod beingy threaded and engaging a threaded portion ofone head, a clutchsleeve mounted rotatively upon said rod, means foractuating the clutch-sleeve indirections alternating as the brakes areapplied and released, means for maintaining betweensaid adjusting-rodand each of theheads a longitudinal pressure which is Constantindirection but variable in amount according to the longitudinal stressesbetween the brakelevers, and means for maintaining a uniformclutchsfriction between the clutch-sleeve and adjusting rod greater thanthe friction between said rod and the heads during free movement of thebrake-levers and less than the friction 'between the rod and headsduring the resisted movement of the 4levers occurring after thebrake-shoes engage the wheels.

9. In a slack-adjuster for brakes, an auto! inatically' extensiblebrake-lever-connection including apair of screwthreaded membersrelatively rotatableto vary the length ofthe` connection, meansfrictionally connected with one of said members for rotating they sameto elongate the .connection when the slack is excessive, and a dctentcarried by one of said threaded membeis and yieldingly engaged with theother, the latter member having a portion engageable with said detent toprevent extension of the connectionbeyond a predetermined limit.-

iO. Ina slack-adjuster for brakes, an ladjusting-rod having a threadedportion, a tubular head inclosing thethreaded portion of theadjusting-rod toform a housing therefor, said head being internallythreaded to en gage the threaded portion of the' rod, the head having aAlateral opening vintersecting the threaded portion in which the rod isen gaged, a membermovably disposed in said lateral opening, the rodhaving anunderciit recess in the sido thereof adapted toregister withsaid lateral opening, and means for actuatingsaid member to enter Saidrecess as the latter kcomes into register therewith dur- Y pin extendingtransversely through the forked head and brake-lever to pivotally con`nect the same, and cheek-plates carried by y the head and arranged toclosely embrace the sidesofthe lever at a distance from said fulcrum-pinto limit movement of ,the` head about the axis of ther adjusting-rodwhen the vfulcrum-pin becomes worn and loose.`

CHARLES o. ANDERSON.

